1. Field of the Invention
The present invention relates to a signal generator, a method for generating signal patterns, a corresponding computer program, and a machine-readable memory medium which includes such a program.
2. Description of the Related Art
So-called arbitrary waveform generators (AWGs) with analog output via digital-analog converters (DACs) are well known. These types of devices typically operate according to the basic principle of direct digital synthesis (DDS), which may be implemented not only by conventional digital signal processors (DSPs) or application-specific integrated circuits (ASICs), but also with the aid of a field-programmable gate array (FPGA).
Published Chinese patent application CN 103176503 A (published Jun. 26, 2013) provides a DDS signal generator and an amplitude control method for this purpose. The DDS signal generator includes a main control unit, an FPGA module connected thereto, and a composite DAC which in turn is connected to the FPGA module, the main control unit being used for assigning amplitude compensation coefficients and reference voltage values to allow a sum of a bit width of the amplitude compensation coefficients and the bit width of the reference voltage values to be greater than or equal to the bit width of the waveform scanning points. The FPGA module includes a waveform memory for storing waveform scanning points, and a digital multiplier used for multiplying the waveform scanning points by the amplitude compensation coefficients in order to obtain a digital waveform variable and transmit the digital waveform variable to a data DAC installed within the composite DAC. A signal program initiation control module is used for converting the reference voltage values into an SPI form and transmitting them to an amplifier DAC within the composite DAC. Lastly, the composite DAC converts waveform values in the data DAC into analog values according to the reference voltage values in the amplifier DAC.